An influential ecologist whose work on plants has helped scientists gain a deeper understanding of evolution and the impact of climate change has been named NSW's Scientist of the Year.

Professor Mark Westoby, from Macquarie University, was honoured at Government House on Monday night for his extensive work on ecoystems, which he described as "the most complicated research problems around".

Over the past two decades, Professor Westoby pioneered "trait-based ecology", which involves using the features of a wide range of plants to categorise species into "functional types". The data can be used to explain patterns of species occurrence and abundance.

"My work is on the similarities and differences between plant species and how they make a living," he said.

He was humbled by the award: "It's a huge honour, I'm very, very surprised. I feel not remotely deserving, but it's nice to know someone thinks well of your work."

Also at the 2014 NSW Science & Engineering Awards, Kostya Ostrikov from the CSIRO took home the Excellence in Mathematics, Earth Sciences, Chemistry and Physics prize, and Benjamin Oldroyd from the University of Sydney and Nicholas Talley the University of Newcastle both nabbed the Biological Sciences trophies.